Lexis has an extensive library of law journal articles, but its resources generally don't go back further than the 1980s. Articles from the Boston University Law Review are only available from 1982 to the present. The volumes of the Rutgers Law Review only date from 1992 onwards. Even Harvard Law Review articles have only been uploaded beginning with volume number 96, published in 1982.
If you're reviewing a brief or expert report that cites to law journal articles from the 1970s and earlier use HeinOnline's Law Journal Library. Hein has scanned and text searchable copies of hundreds of law review articles dating back to the 19th century. The Boston University Law Review's articles are available from 1921 onwards; Rutgers Law Reviews articles go back to 1947; and a full set of the Harvard Law Review from its first volume in 1887 can be downloaded. Articles published in recent years including 2018 are available for each journal as well.
Hein allows you download specific articles as individual PDFs.